diff -Nuar a/SConstruct b/SConstruct
--- a/SConstruct	2020-04-05 19:19:54.000000000 +0000
+++ b/SConstruct	2021-03-12 06:06:22.457277494 +0000
@@ -1107,7 +1107,6 @@
     else:
         env.Append(CXXFLAGS=[
             '-fvisibility=hidden',
-            '-O3',
         ])
 
     if compiler == 'gcc' and compiler_ver[:2] < (4, 6):
